Carbureter



J. B. S. BOOTH.

C'ARBURETER.

APPLICATION FILED JUNE 21. I918.

1,362,468, Patented Dec. 14, 1920.

5 SHEETS-SHEET 1.

J. B. S. BOOTH.

CYARBURETER.

APPLICATION FILED JUNEZI, 1918.

1,362,4 8, Patented Dec.14,1920.

5 SHEETS-SHEET 2- J. B. S. BOOTH.

CARBURETER.

APPLICATION FILED JUNEZI. I918.

Patented Dec. 14, 1920.

5 SHEETS-SHEET 3.

J. B. S. BOOTH.

CARBURETEB.

APPLICATION FILED JUNEZI. I918.

Paten ted Dec. 14, 1920.

5 $HEETS-SHEET 4.

J, B. S. BOOTH.

CARBURETER.

- APPLECATION FILED JUNE 21, I918- 1,362,4 s, Patented Dec. 14,1920.

'5 SHEETSSHEET 5.

PATENT 'FFICE.

JOSEPH BOURDAS SMITH BOOTH, 03E SIDGUP, ENGLAND.

oannonnrnn.

Application filed June 21, 1918.

,T 0 all whom it may concern:

Be it known that I, Josnrrr' Bounces SMITH Boo'rn, a subject or? theKing of Great Britain, residing at Sidcup, Kent. England, have inventedcertain new and useful Improvements in Carburetors, of which thefollowing is a specification.

This invention relates to carburetors and has for its chief obj ect toprovide mechanism for automatically controlling the quantity and qualityof the explosion mixture to develop and maitnain an engine speed withinthe limits of the power of the engine as dic tated and determined by thedriver through appropriate mechanism.

According to the present invention the air supply or inlet and themixture outlet or de livery to the engine or motor are regulated bymechanism automatically operated to determine a quantity and quality ofmixture required to develop and maintain an engine speed as dictated bya device which is under the control of the driver. in carrying theinvention into eflect the quality and quantity of mixture required forall speeds and powers,to be developed, within the limits of the power ofthe engine, are automatically controlled by regulating the air inlet andthe mixture delivery conveniently each by a throttle or similar valve,and these valves are capable of being automatically operated separately,or relatively, and also simultaneously or together by the automaticmechanism. One of the valves is situated around the jet or nozzle or onthe air inlet side of the carburetor and the other is situated on theengine side of the carburetor. Conveniently the mechanism which governsor controls the movements of the two valves comprises pistons which areoperated by fluid circulated by a fluid-pressure pump that is drivenfrom or'by the engine supplied by the carbureter.

The fluid delivered by this controlling pump passes into a cylinder inwhich one of the pistons is situated and moves the piston which opens oreileots or permits the opening oi the throttle valve controlling the airinlet and this movement may also operate the throttle valve on theengine side of the carbureter. When this primary piston has been moved acertain distance, an outlet valve from the cylinder is opened and aportion. of the fluid passes to another cylinder, in which the other orsecondary piston is situated, and effects the movements of this piston.This movement of the piston in the Specification of Letters Eatent.

latented Dec. 14, 1920.

Serial No. 241,279.

second cylinder operates the throttle valve on the engine side of thecarburetor, and it may effect the movement of both throttle valvestogether or relatively to one another. The extent to which the secondpiston is moved is dependent upon the position of the first piston asdetermined by the speed at which the engine is running the constantspeed required under varying loads as dictated by the device which isunder the control of the driver. The throttle valve controlhng the airinlet is primarily moved by its controlling piston in direct proportiont thespeed of the engine, since the pump driven by the engine deliversfluid directly to the cylinder of the piston, and the throttle valve onthe engine side of the carburotor is moved by the piston working in thecorresponding cylinder to maintain the speed dictated by the driversince the movement of the controlling piston is determined by the amountof fluid entering the cylinder and permitted to act on the piston inaccordance with the position of the. control device or valve as dictatedby the driver.

Referring to the accompanying drawings:

Figure 1 is a section diagrammatic elevation of one form of controlmechanism embodying the present invention.

Fig. 2 is a similar view of a modified arrangement.

Fig. 3 is a sectional elevation of another modified construction.

Fig. 4t is a plan of Fig. 3.

Fig. 5 is an end elevation of Fig. 4.

Fig. 6 is a sectional elevation on the line 6-6 of Fig. 5.

Fig. is a sectional view of the two throttle valves.

Fig. 8 is a perspective view of the arrangement illustrated in Figs. 3to 7, and Figs. 9 and 10 are detailed views showing the leverconnections between the valves and the pistons in different positions.

A. is the throttle valve controlling the air supply to the nozzle: B thethrottle valve controlling the mixture to the engine, and O is theprimary piston which is first acted upon by the fluid from the pump: Dthe secondary piston which is acted upon by the fluid from the cylinderof piston C: E is the pump, and F the valve which is under the controlof the driver.

Referring first of all to the arrangement shown in Fi 1.

The valve is in the form of a bell-shaped structure and is disposed overthe jet or nozzle G situated in a conduit or passage G When the engineis not running this valve is in its closed down position. Air enters theconduit G at g and passes under the edge of the valve A in quantitydepending upon the extent to which the valve A is moved by the piston G.

The pump E, which is preferably a gear pump, is driven through a shaft 6and gearing e from a moving part of the engine and is situated in afluid containing casing E and delivers the fluid under the piston Gcausing it to move'in its cylinder.

As the pump is driven from the engine the amount offluid delivered tothe cylinder 0 of the piston C is directly dependent upon andproportional to the speed of the engine, so that the extent of openingof the valve A in this case is directly dependent upon the speed atwhich the engine is running.

The fluid passes from the cylinder 0 by a valve-controlled port 0 In thepresent embodiment the piston G acts as a valve for which purpose it isformed with a cut away or tapering part 0 The higher the piston C israised in the cylinder in accordance with the speed of the engine, asaforesaid,

the greater is the extent to which the port 0 is uncovered and thegreater is the quantity of fluid which passes from the cylinder by theport 0 to the cylinder (Z in which the secondary piston D is situated.

The piston rod C of the piston C is connected to a lever A one end ofwhich, in the [present example, is fulcrumed ,to stationary support 6 ata. The other end of the lever A is connected to the valv A by a link AThe fluid circulated by the pump and passing from the cylinder 0 by theport 0 and depending in quantity on the height to which the piston C hasbeen operated, is led by a conduit E to the cylinder d.

The piston D has a piston rod D which is connected to a lever B one endof which is fulcrumed to a stationary part at a/and the other end isconnected by a link B to an arm B on the second throttle valve B, whichis situated as shown in the supply pipe G on the engine side of thecarbureter. The valve B, when the engine is not running, is fully openas indicated in lommunicating with the cylinder d and with the well inthe pump chamber is a port F in which is situated the control valve F.The fluid entering the cylinder (Z from the conduit E tends to raise thepiston D, and'the extent to which the piston D is raised and thereforethe extent to which the throttle B is operated depends upon the relativepositions of pistons G. and D as determined by the speed of. the enginsand the; position ofrthe. controlsvalve F which is operated by thedriver through suitable mechanism. The fluid passing through the valve Freturns to the chamber and is again available for the pump. The drivercloses or opens the valve F to a greater or less degree in accordancewith the speed at which he desires or re the engine to run. Should thequantity of fluid entering the cylinder cl be greater than can passthrough the controlling valve F the piston D will be moved and cause aclosing down of the valve B thus reducing the demand on the carbureterand a reduction of engine speed. The reduced engine speed will result inless liquid being deliveredv by the pump to the cylinder of piston C sothat the piston C will move backward by gravity or by a spring and'apartial closing of the controlling throttle A take place. This settingof the valve F has thus an immediate effect upon the position of thethrottles A and B and thus the quantity and quality of the mixturesupplied by the carbureter are automatically controlled by the valves Aand B.

In the modified construction illustrated in Fig. 2 the lever A which isoperated by the piston C and is connected to the throttle A, instead ofbeing fulcrumed to a stationary part as described with reference to Fig.l, is fulcrumed to the lever B which is opthrottle B.

The valve A is thus opened by the movement of the primary piston C, asin the previously described arrangement, and thereafter may be moved toa certain extent by the movement of the piston D since any movement ofthe piston D will be transmitted to lever B thence to lever A which,turning on its pivotal connection a with the piston rod 0 operates thevalve A relatively to the valve B.

The throttle valve A is so set by the first movement of the primarypiston C that the engine suction at all speeds produces a correctmixture with the minimum throttling effect thus determining the highestpower the engine is capable of exerting. This latter, being much greaterthan would be required normally, would result in a rapid increase ofspeed up to maximum but for the action of the secondary'piston D, theposition of which is determined by the excess of fluid pumped beyondthat permitted to escape by the valve F, and this piston D acting uponthe valves B and A through levers B and A dictates or .determines thespeed of the engine in accordance with the amount of opening of thevalve F. The amount of fluid passing through the valve F determines theamount ton D thus closing down practically the two throttles A and B;should the engine speed fall, the amount of fluid passing throughthe,valve F, being in excess of the quantity pumped, the secondarypiston D will be moved back by gravity or by a spring, thus opening boththrottle valves A and B the amount required to raise the engine speedand again strike and maintain a balance between the amount of fluidpumped and the amount permitted to escape by valve F.

This arrangement possesses advantages over the arrangement describedwith reference to Fig. 1 since it takes cognizance of the fact that fora given speed of the engine various degrees of power may be required andby coupling the lever A to the lever B of the piston D, the valve A isdirectly controlled not only by the speed of the engine through pump Eand piston C but also directly by the movements of the piston D inaccordance with the amount of fluid passing to the cylinder d and thedegree of opening of the valve F determined by the driver. For example,as applied to a motor vehicle, when the vehicle is descending a hill andis assisted by gravity, the speed of the engine may be maintained orincreased but the demands on the carbureters are not increased. Thevalve B will be closed down according to the amount of the fluidentering the cylinder (Z and the piston C will be in a position to holdthe valve A open, thus unless the means above described for controllingthe valve A are provided a wrong quality of mixture will be supplied. Byconnecting the valve A with the lever B of the piston B, however,whenever the valve B is closing down, in conditions such as referred to,a corresponding closing down of valve A will take place, irrespective ofits movements under the influence of the piston A.

Referring now to the arrangement illustrated in Figs. 3-10, the twothrottle valves A and B are in the form of segments rotatably mountedupon coaxial shafts A B respectively, situated in a casing G surroundingthe jet or nozzle G and these shafts are connected with or coupled withtheir respective operating mechanism.

The pistons C and D are disposed in their cylinders which are arrangedhorizontally in a block disposed in the pump casing E According to thisembodiment of the invention the valves A and B are both in their closeddown position when the engine is not running.

The throttle valve A, which, as already stated, controls the air inletopening 9 is not positively connected with the piston C as in previouslydescribed arrangements, but the movements of piston C are utilized toposition a stop (3 which regulates the extent of opening of the valve Aaccording to the speed of the engine. The stop (3 is mountend on an arm0 on the upper end of a sleeve C which is rotatably mounted on the shaftA The rod C of piston C is con nected to another arm C on the sleeve (3and secured to a third arm C on the sleeve 0 is one end of a spring Cthe other end of which is fixed to a stationary member in the casing.This spring is so arranged that it opposes the turning of the sleeve (1under influence of the piston C.

Pivotally connected to a boss on the arm C concentric with the stop C isone end of a link A to the other end of which is pivoted a link A* whichis connected with one end of a lever A which lever is securedintermediate its ends to the upper end ofthe shaft A to which the valveA is secured. The end of the lever A opposite to that to which the linkA is connected has attached to it one end of a spring A, which is ofless power than the spring C and has its other end secured to a fixedpoint. Between the points of its attachment to the spring C and theshaft A the lever A bears against the stop C Pivoted to the link Acoaxially with the link A is one end of a link B, the other end of whichis adjustably secured to one end of a lever B which is fixedintermediate its ends to the shaft B of the valve B and the other end ofthis lever B is pivotally secured to the rod D of piston D.

Through the connections of the links A A and B with the sleeve operatedby the piston C on the one hand and with the levers A and B connectedrespectively with the valves A and B, both valves can be operated by themovements of either piston. The links constitute a differential gear sothat, if the movement of one piston is checked or opposed by the other,the two valves are moved relatively to each other or to difierentextents. The link B can be adjusted on the arm of the lever B so as to cand d is situated a control valve C which.

is operated by the movements of the piston C. 0n the sleeve C to whichthe rod of the piston C is attached, is'an arm C can rying a stud towhich a lever C of the valve 22 is connected by a link C This valve isoperated in proportion to the extent of travel of the piston G andcontrols the fluid passing from the cylinder 0 to the cylinder 41.

The valve F by which the driver dictates the speedof the engine,controls as in previous examples, the outlet from the cylinder cl. Thisvalve may be constructed as in the previously described arrangements orit may be of other appropriate form. Pref-- erably, however, it is inthe form illustrated in Fig. 6, as in this form the outlet controlled bythe valve is automatically varied, within limits, in accordance withvariations of pressure due to the variable tension of. the spring A, andthus the valveopening is relative to the position of the lever operatedby the driver to set the valve, and the liquid pressure acting on thevalve, to maintain a flow corresponding to the position of the controllever. The valve proper f is arranged to work relatively to a seating fand the stem 7 of the valve is screwed through a block 7' which is freeto slide in a tube 7. The block has a spiral groove around its exterior,and the convolutions of the spring rest in this groove so that the blockis adjustably connected to a spring Normally the block is situated at orabout midway of the length of the spring. The tube 7 is a sliding fit ina casing f and one end of the spring 7 bears on the upper end of thetube 7 while the other end bears against the lower end of the casing f.The lever controlled by the driver acts upon the tube 7, by depressingwhich the spring will becompressed and the valve more or less closed,but the spring permits a movement of the valve independently of thecontrolling mechanism inaccordance with the fluid pressure acting uponthe valve. When the engine is not running the valves A and B are in theposition shown in the drawings.

When the engine is turned for startin fluid is immediately forced by thepump It into the cylinder 0 moving the primary piston 0 against theaction of spring C and opening the valve 0 permitting fluid to pass tothe cylinder d of the secondary piston D. The movement of piston Callows the spring A to act and through the lever mechanism abovedescribed the valves A and B will be opened. The two valves move inunison and the piston D moves inward as the fluid in cylinder cl passesout by valve F, and this movement will continue until, by the movementof piston C the valve 0 is opened to allow a quantity of fluid, equal tothat delivered by the pump, to pass to the cylinder d. When this pointis reached, the movements of both pistons'ceases and the valves A and Bare in position to insure the production of a perfect mixture for thatspeed of the engine. When the engine commences to fire, an increase inits speed takes place resulting in an increased flow of liquid from thepump and a consequent opening of both valves A and B due to the outwardmovement of the pistonC still in such relation to the increasing speedas to produce the'largest valveopening that will give a perfect mixture.Unless checked the continuance of these conditions would soon result inthe engine reachingmaximum.speed.

But as the delivery of fluid by the pump increases with the increasingspeed of the enthat its speed will continue to rise, the valve A will bestill. further opened under action of the piston C, but as the movementof piston D, and therefore valve B, has been checked, by the fluid inthe cylinder d, the valve A alone opens further through the liquid inthe cylinder 0 acting on piston C which through the aforesaid linkmechanism operates the valve A. The increased speed of the enginefinally results in the quantity of fluid entering the cylinder d beingin excess of what can pass through the valve F, which moves the piston Doutward and operates both valves in a closing direction, the amount ofclosing being diflerential on account of the link mechanism. Shouldgreater effort or power be demanded from the engine, due by gradient,increased weight, bad road surface, windage, or other cause, the ensuingloss of speed results in a decreased pump-delivery and the piston D willbe moved to further open the valve D while the valve A will also bemoved inan opening direction by the movement of the piston C and also byreason of its connection with the piston D. The movements of the twovalves will continue to give an increasing volume of mixture to meet thenew demand for power until maximum power at the particular dictatedspeed is attained. Should this speed be reached before the power-demandis met, speed will automatically be reduced as the engine will beoverloaded.

On theother hand, if the engine continues to run at a speed greater thanthat dictated by the driver, independently of the engine efl'or t, forexample with a vehicle descending a steep gradient, the piston D willcontinue to open valve B until a passage B in the valve establishescommunication between the atmosphere through a by-pass B and the conduitbetween the carbureter and the engine and the lever mechanism will thenbe in the position shown in Fig. 10.

Mechanism controlling'the advance or retarcl of the ignition device maybe connected with the carbureter control mechanism, for example, byconnecting the ignition control lever with theprimary piston C or otherconvenient part.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

.l. Ina-carbureter, in combination, a fuel supply device, an air inletvalve, a mixture outlet valve, separate control means for both valves,mechanism operatively connected with a moving part of the engine andwith the valve control means, and means controlled by the driver forvarying the control means of the air and outlet valves to controlautomatically the relative position of the said air inlet valve andmixture outlet valve to automatically provide a quality and quantity ofmixture to automatically develop and maintain under varying loads thespeed dictated by the position of the driver control means.

2. In a carbureter, the combination with a fuel supply device, means forcontrolling the air supply and means for controlling the mixturedelivery, of control mechanism for the air supply means, controlmechanism for the mixture delivery means, means connected with a movingpart of the engine for operating first one of the control means andthereafter the other control means, and hand-controlled means forvarying the position of the control means.

In a carbureter, the combination with a liquid fuel supply device, meansfor con trolling the air supply on one side of the fuel device, andmeans for controlling the mixture delivery on the other side of the fuelsupply device, of controlling means for the air supply device,controlling means for the mixture delivery device, means operativelyconnected with a moving part of the engine for variably operating bothcontrol means, and engine speed determining means under the control ofthe driver for varying the operative eflect on both of the control meansof the operative means connected with the engine.

l. In a carbureter, the combination with a liquid fuel supply device,means for controlling the air supply on one side of the fuel supplydevice, and means for controlling the mixture delivery on the other sideof the fuel supply device, of operating mechanism for the air controlmeans, operating mechanism for the mixture control means, meansconnecting both these operat ing mechanisms, means dependent for itsmovement upon the speed of the engine for moving one of the operatingmeans, and means controlling the relative movement of both operatingmeans, also connected with the engine driven member, and an engine speeddetermining device set by the driver and operative also upon the meansfor controlling the movement of both the air and mixture control means.

5. In a carbureter the combination with a fuel supply device, means forcontrolling the air inlet on the one side of the fuel sup ply and meansfor controlling the mixture outlet on the other side of the fuel supply,of actuating means for one'control device,

means connecting this actuating means with a moving part of the engine,actuating means for the other control device, engine speed determiningmeans under the control of the driver, and operatively con nected withthe second actuating means, and means whereby the actuating mechanism ofthe first control device is also operative upon the second actuatingmeans.

6. In a carbureter, the combination with an air inlet valve and amixture delivery valve, of a piston working in a cylinder, meansoperatively connecting the piston with the air inlet valve, a secondpiston. working in a cylinder, means operatively connecting the pistonwith the mixture delivery valve, a pump arranged to deliver fluid to oneof the cylinders, means controlling the delivery of' fluid to the secondcylinder, means connecting the pump with a moving member of the engine,and means under control of the driver for regulating the discharge offluid from the second cylinder.

7 In a carbureter, the combination with an air inlet valve and a mixturedelivery valve, of a piston moving in a cylinder, means connecting thepiston with the air inlet valve, a second piston moving in a cylinder,means connecting the piston with the mixture delivery valve, a pump,means whereby the pump can deliver fluid first to one and then to theother cylinder, means connecting the pump with a moving member of theengine and a device under control of the driver for regulating an outletfrom the second cylinder.

8. In a carbureter, the combination with an air inlet and a mixtureoutlet, of a valve in the air inlet, a valve in the mixture outlet, apiston working in a cylinder, means connecting the piston with the airinlet valve, a second piston working in a cylinder, means connecting thepiston with the valve in the mixture outlet, means connecting the valvesso that they can be operated by either piston, a pump, means whereby thepump can deliver fluid first to one cylinder and then to the othercylinder, means connecting the pump with a moving part of the engine,and a device under control of the driver for regulating an outlet fromthe second cylinder.

9. In a carbureter, the combination with an air inlet valve and amixture delivery valve, of a piston working in a cylinder, meansconnecting the piston with the air inlet valve, a second piston workingin a cylinder, means connecting said piston with the mixture deliveryvalve, a pump in direct communication with the first cylinder, meansoperated by the first piston controlling communication between the pumpand the second cylinder, means connecting the pump with a moving part ofthe engine, and a device under control of the driver for regu-' latingan outlet from the second cylinder.

10. In a oarbureter, the combination with an air inlet valve and amixture delivery valve, of a piston working in a cylinder, meansconnecting the piston with the air inlet valve, a second piston workingin a cylinder, means connecting said piston with the mixture deliveryvalve, means connecting the valves to be actuated by either piston, of apump in direct communication with the first cylinder, means operated bythe first piston controlling the supply of fluid to the second cylinder,means connecting the pump to a moving part of the engine, and a deviceunder the control of the driver for regulating the outlet from thesecond cylinder.

11. In a carburetor, the combination with an air inlet valve and'amixture delivery valve, of a piston working in a cylinder, meansconnecting the piston with the air control valve, a second pistonworking in a cylinder, means connecting the piston with the mixturedelivery valve, means connecting the valves to be controlled by eitherpiston, a pump in direct communication with one cylinder, means operatedby the first piston controlling communication between the pump and thesecond cylinder.

12. In a oarbureter, the combination with means for controlling the airinlet and means for. controlling the mixture outlet, of o a pump, meansconnecting the pump with a moving part of the engine, means connectingthe pump with the air inlet and mixture outlet controlling means, andmeans operated by the driver connected with the controlling means.

13. In a carburetor having an air inlet and a mixture outlet, thecombination of a circulating pump, means operated by the driver fordetermining an engine speed, and means connected with the pump forautomatically controlling the quantity and quality of the mixturerequired to develop the speed under varying loads determined by thedriver.

14. In a oarbureter, the combination with a pump, means connecting thepump with a moving part o1 the engine, and speed control means operatedby the driver, ofineans for automatically regulating the air inlet andmixture outlet of the oarbureter, means connecting the automatic controlmeans with the pump and means connecting the control I means with thespeed regulating device con trolled by the driver.

15. In a oarbureter, the combination ofa pump, means connecting the pumpwith a moving part of the engine, means controlling the air. inlet,means controlling the mixture outlet, a cylinder, means establishingcommunication between the pump and the cylinder, a second cylinder,means controllingcommunication between the pump and :1. ,eeenes thesecond cylinder, means operated by the driver controlling the dischargefrom the second cylinder, means connecting a piston in one cylinder withthe air inlet control and means connecting a piston in the othercylinder with the mixture control.

16. In a carbureter, the combination with an air inlet valve and amixture outlet valve, ofa pump, a piston working in a primary cylindercommunicating with the pump, a piston working in a secondary cylinder,means operated by the primary piston controlling admission of fluid tothe secondary cylinder, means operated by the driver controlling theoutlet from the secondary cyl- "inder, levermechanism connecting theprimary piston with the air inlet valve and lever mechanism connectingthe secondary piston with the mixture controlling valve. 17. In aoarbureter, the combination with an air inlet valve and a mixturedelivery valve, of a piston working in a primary cylinder, levermechanism connecting the air inlet valve with the piston, a pistonworking in a secondary cylinder, lever mechanism connecting the pistonwith the mixture delivery valve, lever mechanism connecting both valveswith both pistons, a pump in direct communication with the primarycylinder, a valve operated by the primary piston controlling the inletto the secondary cylinder, a valve operated by the driver controllingthe outlet from the secondary cylinder, and means connecting the pumpwith a moving part of the engine.

18. In a oarbureter, the combination with an air inlet control valve anda mixture delivery valve, of a piston working in a primary cylinder, astop carried by the piston, a link connected with the stop, a leverbearing against the said stop, a second link connecting the aforesaidlink and lever, a connection between said lever andthe air inlet valve,a lever connected with the mixture delivery valve, a piston working inasecondary cylinder, a connection between the piston and the lever of thedelivery valve, link mechanism connecting the lever of the deliveryvalve with the aforesaid stop, a pump in open communication with theprimary cylinder, a valve'between the primary and secondarycylinders,.means connecting said valve with the primarypiston, a deviceoperated by the driver controlling the outlet from the secondarycylinder, and means connecting the pump with a moving part of the enine.

19. na oarbureter, the combination with an air inlet valve and a mixturedelivery valve, of a piston working in a cylinder, a second pistonworking in a cylinder, a difierential mechanism connectingboth pistonswith both valves, a pump in direct communication with one cylinder andin indirect communication with the other cylinder,

and means operated by the driver for conicslrolling the outlet from oneof the cylin ers.

20. In a carbureter, the combination with an air inlet valve, and acombined mixture delivery and air by-pass valve, of a piston working ina primary cylinder, a piston working in a secondary cylinder, differemtial mechanism connecting the pistons and the valves, a pump in directcommunication with one cylinder, a valve between the cylinders, aconnection between the valve and the primary piston, and a valveoperated by the driver controlling the outlet from the secondarycylinder.

In testimony whereof I afiix my signature in presence of two witnesses.

JOSEPH BOURDAS SMITH BOOTH. Witnesses:

W. Wme, H. F. BLAGKETT.

